1、Designation: D 1434 82 (Reapproved 2003)Standard Test Method forDetermining Gas Permeability Characteristics of Plastic Filmand Sheeting1This standard is issued under the fixed designation D 1434; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、 of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the estimation of the steady-state rate of transmission of a gas th
3、rough plastics in the formof film, sheeting, laminates, and plastic-coated papers orfabrics. This test method provides for the determination of (1)gas transmission rate (GTR), (2) permeance, and, in the case ofhomogeneous materials, (3) permeability.1.2 Two procedures are provided:1.2.1 Procedure M
4、Manometric.1.2.2 Procedure V Volumetric.1.3 The values stated in SI units are to be regarded as thestandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety
5、and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 618 Practice for Conditioning Plastics for TestingD 1898 Practice for Sampling of Plastics33. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1
6、gas transmission rate, GTR the quantity of a givengas passing through a unit of the parallel surfaces of a plasticfilm in unit time under the conditions of test. The SI unit ofGTR is 1 mol/(m2s). The test conditions, including tempera-ture and partial pressure of the gas on both sides of the film,mu
7、st be stated. Other factors, such as relative humidity andhydrostatic pressure, that influence the transport of the gasmust also be stated. The inch-pound unit of GTR, a commonlyused unit of GTR, is 1 mL (STP)/(m2d) at a pressuredifferential of one atmosphere.3.1.2 permeance, Pthe ratio of the gas t
8、ransmission rateto the difference in partial pressure of the gas on the two sidesof the film. The SI unit of permeance is 1 mol/ (m2sPa). Thetest conditions (see 5.1) must be stated.3.1.3 permeability, Pthe product of the permeance and thethickness of a film. The permeability is meaningful only forh
9、omogeneous materials, in which it is a property characteristicof the bulk material. This quantity should not be used unlessthe constancy of the permeability has been verified usingseveral different thicknesses of the material. The SI unit of P is1 mol/(msPa). The test conditions (see 3.1) must be st
10、ated.NOTE 1One millilitre (STP) is 44.62 mol, one atmosphere is 0.1013MPa, and one day is 86.4 3 103s. GTR in SI units is obtained bymultiplying the value in inch-pound units by 5.160 3 1010. Additionalunits and conversions are shown in Appendix X1.3.1.4 steady statethe state attained when the amoun
11、t ofgas absorbed in the film is in equilibrium with the flux of gasthrough the film. For Method V this is obtained when the GTRis constant.4. Summary of Test Method4.1 The sample is mounted in a gas transmission cell so asto form a sealed semibarrier between two chambers. Onechamber contains the tes
12、t gas at a specific high pressure, andthe other chamber, at a lower pressure, receives the permeatinggas. Either of the following procedures is used:4.1.1 Procedure M In Procedure M the lower pressurechamber is initially evacuated and the transmission of the gasthrough the test specimen is indicated
13、 by an increase inpressure.4.1.2 Procedure V In Procedure V the lower pressurechamber is maintained near atmospheric pressure and thetransmission of the gas through the test specimen is indicatedby a change in volume.5. Significance and Use5.1 These measurements give semiquantitative estimates forth
14、e gas transmission of single pure gases through film andsheeting. Correlation of measured values with any given use,such as packaged contents protection, must be determined by1This test method is under the jurisdiction ofASTM Committee F02 on FlexibleBarrier Materials and is the direct responsibilit
15、y of Subcommittee F02.10 onPermeation.Current edition approved July 30, 1982. Published November 1982. Originallypublished as D 1434 56 T. Last previous edition D 1434 75.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Ann
16、ual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.experience. The gas transmission rate is affected by conditionsn
17、ot specifically provided for in these tests, such as moisturecontent (Note 2), plasticizer content, and nonhomogeneities.These tests do not include any provision for testing seals thatmay be involved in packaging applications.NOTE 2The tests are run using gas with 0 % moisture changes.5.2 Interlabor
18、atory testing has revealed that permeancesmeasured by these procedures exhibit a strong dependence onthe procedure being used, as well as on the laboratoryperforming the testing. Agreement with other methods issometimes poor and may be material-dependent. The materialsbeing tested often affect the b
19、etween-laboratory precision. Thecauses of these variations are not known at this time. It issuggested that this method not be used for referee purposesunless purchaser and seller can both establish that they aremeasuring the same quantity to a mutually agreed upon level ofprecision.5.3 Use of the pe
20、rmeability coefficient (involving conver-sion of the gas transmission rate to a unit thickness basis) is notrecommended unless the thickness-to-transmission rate rela-tionship is known from previous studies. Even in essentiallyhomogeneous structures, variations in morphology (as indi-cated, for exam
21、ple, by density) and thermal history mayinfluence permeability.6. Test Specimen6.1 The test specimen shall be representative of the material,free of wrinkles, creases, pinholes, and other imperfections,and shall be of uniform thickness. The test specimen shall becut to an appropriate size (generally
22、 circular) to fit the test cell.6.2 The thickness of the specimen shall be measured to thenearest 2.5 m (0.1 mil) with a calibrated dial gage (orequivalent) at a minimum of five points distributed over theentire test area. Maximum, minimum, and average valuesshould be recorded. An alternative measur
23、e of thicknessinvolving the weighing of a known area of specimens having aknown density is also suitable for homogeneous materials.7. Conditioning7.1 Standard ConditioningCondition all test specimens at23 6 2C (73.4 6 3.6F) in a desiccator over calcium chlorideor other suitable desiccant for not les
24、s than 48 h prior to test inaccordance with Practice D 618, for those tests where condi-tioning is required. In cases of disagreement, the tolerancesshall be 6 1C (6 1.8F).7.2 Alternative ConditioningAlternatives to 7.1 may beused for conditioning the specimens provided that theseconditions are desc
25、ribed in the report.8. Sampling8.1 The techniques used in sampling a batch of material tobe tested by these procedures must depend upon the kind ofinformation that is sought. Care should be taken to ensure thatsamples represent conditions across the width and along thelength of rolls of film. Practi
26、ce D 1898 provides guidelines fordeciding what procedures to use in sampling a batch ofmaterial. Enough specimens must be tested to ensure that theinformation obtained is representative of the batch or other lotsize being tested.PROCEDURE M(Pressure changes in the manometric cell may be determinedby
27、 either visual or automatic recording.)MANOMETRIC VISUAL DETERMINATION9. Apparatus9.1 The apparatus shown in Fig. 1 and Fig. 2 consists of thefollowing items:49.1.1 Cell Manometer SystemThe calibrated cell manom-eter leg, which indicates the pressure of transmitted gas, shallconsist of precision-bor
28、e glass capillary tubing at least 65 mmlong with an inside diameter of 1.5 mm.9.1.2 Cell Reservoir System, consisting of a glass reservoirof sufficient size to contain all the mercury required in the cell.9.1.3 AdaptersSolid and hollow adapters for measure-ment of widely varying gas transmission rat
29、es. The solidadapter provides a minimum void volume for slow transmis-sion rates. The hollow adapter increases the void volume byabout a factor of eight for faster transmission rates.9.1.4 Cell Vacuum Valve, capable of maintaining a vacuum-tight seal.59.1.5 Plate Surfaces, that contact the specimen
30、and filterpaper shall be smooth and flat.9.1.6 O-Ring, for sealing the upper and lower plates.9.1.7 Pressure Gage, mechanical or electrical type with arange from 0 to 333 kPa absolute. Used for measuringupstream gas pressure.9.1.8 Barometer, suitable for measuring the pressure of theatmosphere to th
31、e nearest 133 Pa.4The Dow gas transmission cell supplied by Custom Scientific Instruments, Inc.,Whippany, NJ, has been found satisfactory for this purpose.5The Demi-G Valve (14-in. IPS) manufactured by G. W. Dahl Co., Inc., Bristol,RI, or a precision-ground glass stopcock, meets this requirement.FIG
32、. 1 Manometric Gas Transmission CellD 1434 82 (2003)29.1.9 Vacuum Gage, to register the pressure during evacua-tion of the system to the nearest 13 Pa.9.1.10 Vacuum Pump, capable of reducing the pressure inthe system to 26 Pa or less.9.1.11 Needle Valve, for slowly admitting and adjusting thepressur
33、e of the test gas.9.1.12 Cathetometer, to measure the height of mercury inthe cell manometer leg accurately. This instrument should becapable of measuring changes to the nearest 0.5 mm.9.1.13 Micrometer, to measure specimen thickness, gradu-ated to 2.5 m (0.1 mil) or better.9.1.14 Elevated-Temperatu
34、re FittingsSpecial cell fittingsare required for high-temperature testing.10. Materials10.1 Test GasThe test gas shall be dry and pure. The ratioof the volume of gas available for transmission to the volumeof gas transmitted at the completion of the test shall be at least100:1.10.2 MercuryMercury us
35、ed in the cell shall be tripledistilled, checked regularly for purity, and replaced with cleanmercury when necessary.10.2.1 WarningVery low concentrations of mercury vaporin the air are known to be hazardous. Guidelines for usingmercury in the laboratory have been published by Steere.6Besure to coll
36、ect all spilled mercury in a closed container.Transfers of mercury should be made over a large plastic tray.Under normal daily laboratory-use conditions, the cells shouldbe cleaned about every 3 months. Dirty mercury is indicatedwhen the drop of the capillary becomes erratic or whenmercury clings to
37、 the side of the capillary, or both. Wheneversuch discontinuities occur, the mercury should be removed andthe cell cleaned as follows:(1) Wash with toluene (to remove greases and oils).(2) Wash with acetone (to remove toluene).(3) Wash with distilled water (to remove acetone).(4) Wash with a 1 + 1 m
38、ixture of nitric acid and distilledwater (to remove any mercury salts that may be present). Thisoperation may be repeated if necessary in order to ensurecomplete cleaning of glassware.(5) Wash with distilled water (to remove nitric acid).(6) Wash with acetone (to remove water).(7) Dry the cell at ro
39、om temperature or by blowing a smallamount of clean dry air through it.11. Calibration11.1 Each cell should be calibrated at the test temperature asfollows (Fig. 3):11.1.1 Determine the void volume of the filter paper fromthe absolute density of its fiber content (Note 3), the weight ofthe filter pa
40、per, and its apparent volume (Note 4). Express thevoid volume determined in this way in microlitres and desig-nate as VCD.NOTE 3Any high-grade, medium-retention qualitative nonashing cel-lulosic filter paper, 90 mm in diameter will be satisfactory for this purpose.Cellulose fiber has an approximate
41、density of 1.45 g/mL.NOTE 4The apparent volume may be calculated from the thicknessand diameter of the filter paper.11.1.2 Determine the volume of the cell manometer legfrom B to C, Fig. 3, by mercury displacement. (Since the voidvolume of the adapters is included in this part of the calibra-tion, t
42、he volume from B to C should be determined twice, oncewith the solid adapter in place, and once with the hollow.) Thisvolume is obtained by dividing the weight of the mercurydisplaced by its density (Note 5). Determine this volume tonearest 1 L and designate as VBC.NOTE 5The density of mercury at 23
43、C is 13.54 g/mL.11.1.3 Determine the volume, in microlitres, of the cellmanometer leg from A to B, Fig. 3, by mercury displacement.6Steere, N. E. “Mercury Vapor Hazards and Control Measures” in Handbook ofLaboratory Safety, N. V. Steere, Ed., CRC Press Inc., Boca Raton, FL, 1979.ASupporting LegsBLow
44、er PlateCUpper PlateDAdapterEVacuum ValveFIG. 2 Schematic View of Gas Transmission CellFIG. 3 Cell Manometer with Test Specimen in PlaceD 1434 82 (2003)3Determine the average cross-sectional area of the capillary bydividing this volume by the length (expressed to the nearest 0.1mm) from A to B. Dete
45、rmine this area to the nearest 0.01 mm2and designate as ac.11.1.4 Determine the area of the filter paper cavity to thenearest 1 mm2. Designate this area as A, the area of transmis-sion.11.1.5 Pour the mercury from the reservoir into the manom-eter of the cell by carefully tipping the cell. Record th
46、e distancefrom the datum plane to the upper calibration line B in thecapillary leg as hB. Record the distance from the datum planeto the top of the mercury meniscus in the reservoir leg as hL.Determine hBand hLto the nearest 0.5 mm.11.2 NBS Standard Reference Material 14707is a polyesterfilm whose p
47、ermeance to oxygen gas has been certified for arange of experimental conditions. The calibration steps in 11.1can be verified by comparing measurements obtained using thismethod of test in the users laboratory with the values providedon the certificate accompanying the SRM.12. Procedure12.1 Transfer
48、 all the mercury into the reservoir of the cellmanometer system by carefully tipping the cell in such a waythat the mercury pours into the reservoir.12.2 Insert the appropriate adapter in the cell body.12.3 Center a filter paper in the lower plate cavity.12.4 Apply a light coating of vacuum grease o
49、n the flatmetal that the surface of the specimen will contact. Avoidexcessive grease.12.5 Place the conditioned specimen smoothly on the lowerlightly greased plate so that it covers the filter paper and theentire exposed face of the lower plate.12.6 Locate the O-ring on the upper plate; then carefullyposition this plate over the specimen and fix the plate withuniform pressure to ensure a vacuum-tight seal.12.7 Connect the line in which the test gas will be subse-quently admitted to the upper plate. (The entire cell is nowdirectly connec
